Regenerative heat exchanger



May 21, 1957 F. w. HARRIS 2,793,022

REGENERATIVE HEAT EXCHANGER Filed Jan. 4, 1954 //v l/E/V TOR. Fo/w WHam/5 5) HTTORNEKS. HARRIS, K1501, P057226: Hake/s REGENERATIVE HEATEXCHANGER Ford W. Harris, Los Angeles, Calif., assignor to Wullf ProcessCompany, Huntington Park, Califl, a corporation of CaliforniaApplication January 4, 1954, Serial No. 401,946

Claims. (Cl. 263-51) The invention relates to the economical utilizationof heat in any process by the use of regenerative masses. These massesrecover and store up heat from waste gases and then give up this heat sothat it can be used in the process. Such regenerative masses have a wideuse in the steel industry, recovering heat from waste gases and beinglater used to deliver the stored heat to air to be used for combustion.Such masses are also used in various chemical processes, such, forexample, as converting various hydrocarbons to other hydrocarbons bypyrolysis.

The word slab as used herein is limited to a brick or slab which isformed from a heat refractory material such as fire clay, or otherceramic material, or from some metals, graphite, or other carbonaceousmaterials. The Word refractory is used herein to denote a material whichresists injury or decomposition when subjected to heat. The wordregenerative as used herein denotes a member or mass which readilyabsorbs and gives up heat.

A regenerative mass denotes a mass of refractory material which haschannels extending therethrough through which gases pass to give up andabsorb heat. Such a mass as hereinafter described may be assumed to havethe form of a cube.

The invention resides in a novel form of slab which is well adapted toform a new and very useful form of regenerative mass.

The drawings show a portion of or entire, slabs and how these slabs arelaid one upon another, in layers, to form a regenerative mass.

Fig. I is a section on a plane shown in dotted lines V-V of Fig. II.

Fig. II is an isometric view of a preferred form of slab.

Fig. III is an isometric view of a partially completed regenerative massdisclosing how the slabs may be laid to break joints and to form slotsthrough which gases may pass and cross channels for equalizing gas flowthrough the mass.

Fig. IV is a section through a regenerative mass made up of the slabsshown in Figs. I and II, showing how these slabs are laid up to producetwo different widths of slot.

The general appearance of the slots as they are seen While being laid toproduce the desired regenerative mass is shown in Fig. III, the slabshaving a length L, a width W and a thickness T. These dimensions, ofcourse, depend upon the use to which the regenerative mass is to he putand the economical limits imposed by the techniques of tile manufacture,the slabs being produced under such technique.

As shown in Fig. I, the slab 1 has a fairly uniform thickness and has aseries of upper grooves 2 and a series of lower grooves 3, these groovesbeing staggered with relation to each other. The upper grooves 2 areseparated by upper bearing surfaces 4 and the lower grooves 3 areseparated by lower bearing surfaces 5. All grooves and bearing surfacesare parallel with each other and each ted States Patent 0 Z,793,ll2.2Patented May 21, 1957 groove is immediately adjacent to a bearingsurface which results in fairly uniform thickness in the slab throughoutthe most of its volume.

A preferred form of slab is shown in the drawings and the preferredproportions of such a slab are shown in Fig. I, the depth of the grooves2 and 3 being assumed as X. The value of X may be varied but. thepreferred proportions will be multiples of X. The depth of the groovebeing assumed as X, the grooves 2 and 3 may have a width 5X and thebearing surfaces 4 and 5 may have a width of 9X, the thickness of theslab being 3X outside the grooves. For example, the value of X may beabout inch, the grooves 2 and 3 being then 1%" wide and the bearingsurfaces being 2%" wide and the slab being A" thick. The abovedimensions are given merely to illustrate the best mode now contemplatedby me of applying the invention. The dimension X may vary widely fordifferent uses but, if the proportions above stated in terms of X arefollowed, the proportion of voids to solid material in the mass will bebetween 20% and 25%.

Slabs may be laid as shown in Fig. IV, forming slots 7, each having adepth and a width 5X extending through the mass.

To produce the desired results, the bearing surfaces 4 and 5 must bewider than the grooves 2 and 3. This provides a solid column of material2X wide along a columnar axis 1112, as shown in Fig. IV, this axis beingprovided by contact between the bearing surfaces 4 and S. This enablesthe regenerative masses to be self-supporting if the plane of the slabsis horizontal. It also permits large masses to be built up of slabshaving the proportions defined in Fig. IV.

Several objects are accomplished by the novel form of regenerative massformed by the slabs, among which are the following:

'(a) The slabs are of uniform thickness, which is important in ceramicmaterials.

(b) The grooves are of relative small depth as compared with theirwidth, for a groove M4" deep in a slab /1" thick would be 1%" wide,which facilitates the'construction of the slab.

(c) The slabs when piled up to form the mass register quite accurately.

Preferably the slabs should be laid as shown in Fig. III in which alljoints are broken by using half slabs 20 and full slabs 21, andproviding narrow cross channels 22. These channels may be X wide andextend across the mass; that is, they may be about as wide as thegrooves 2 and 3 deep. The regenerative masses may be five or ten feetlong in the direction of the slots and the slabs may be 9" long (L). Across channel will then be provided in each layer of slabs every 9". Anobject of these channels is to provide equalization of flow in all thechannels. Each channel connects with all the grooves in each of theslabs bordering the channel and all of the grooves in the bottom of theslabs in the layer above the channel and all the grooves in the top ofthe slabs below the channel. The cross channels are themselves staggeredvertically. In any channel, the better the channel walls, the moreresistance to gas flow and each of the channels tends to slow down gasflow when hot and to speed it up when cold. When regenerative masses areused in some processes, the hotter masses, the higher efficiency of theprocess, and it is highly desirable to heat the mass as close to adestructive temperature as possible; that is, to a temperature at whichthe material of the slabs starts to spall or otherwise deteriorate. Iteven a small portion of the mass is overheated, the mass will rapidlydeteriorate. The channels 22 prevent such deterioration by providing auniform heating of the entire mass.

I claim as my invention:

1. A member which may be used to build up a regen erative mass,comprising: a rectangular slab of heat refractory material bounded bytwo parallel plane surfaces, each of said surfaces havingaseries ofparallel fiat grooves each having a Width of at least five (5) times itsdepth, the grooves on one side occupying intermediate longitudinalpositions with relation to the positions of the grooves on the otherside, each of said grooves having parallel side walls, and each of saidgrooves having a length substantially greater than its Width.

' 2. A member as claimed in claim 1 wherein the grooves on each side ofsaid slab are separated from each other by plane surfaces of the slabsubstantially wider than the width'of the grooves.

3.. A' member as claimed in claim 1 in which the slab has a thickness ofabout three times the depth of the grooves.

'4. A regeneraative mass consisting of superimposed flat rectangularslabs with horizontal slots in the upper and lower plane surfacesthereof extending from front to back of said mass, each of saidslotsbeing formed by a groove, each of said slots having parallel sides andparallel edges, one side being formed by the bottom of said groove andthe other side being formed bythe surface of an overlying or underlyingslab, the horizontal width of vide parallel vertical columns of solidmaterial between said slots from top to bottom of the mass.

5. A regenerative mass as specified in claim 4 having narrow crosschannels formed between ends of adjacent slabs located in the same planeand extending horizontally across the mass, each cross channelregistering with the ends of slots in adjacent slabs located in the sameplane,

and also registering with intermediate portions of slots in overlyingand underlying slabs.

References Cited in the file of this patent UNITED STATES PATENTS1,167,081 Kennedy Jan. 4, 1916 1,364,155 Straight Jan. 4, 1921 1,978,191Porter Oct. 23, 1934 2,473,427 Hasche June 14, 1949 2,622,864 HascheDec. 23, 1952 2,706,109 Odman Apr. 12, 1955

